If I understand correctly, the goal is to match artists that must have
painting that are ALL with the same color. So I think the second OR
would match artists that have SOME painting of matching color, and
some of a different color.
But I guess the important thing here is that Andrey and me showed 2
new capabilities of Cayenne 3.0 that would help with a number of non-
trivial queries.
Andrus
On Jan 10, 2010, at 2:08 PM, Andrey Razumovsky wrote:
Or you can use left joins:
ExpressionFactory.matchExp("paintingsArray+.color",
null).orExp(ExpressionFactory.matchExp("paintingsArray+.color",
blue));
2010/1/10 Andrus Adamchik <[email protected]>
This requires Cayenne 3.0 and EJBQLQuery with subquery. Something
like this
might work:
new EJBQLQuery(
"SELECT a FROM Artist a " +
"WHERE NOT EXISTS " +
"(SELECT p FROM Painting p WHERE p.color <> 'XYZ')";
Andrus
On Jan 7, 2010, at 2:32 AM, Mark Fraser wrote:
Suppose I have an Artists table and a Paintings table with the
usual setup
of the Artist class having a PAINTINGS_ARRAY property. Suppose
further
that
the painting has a "color" property that can be a string or null.
How would I build an Expression such that I get back the Artists
that have
either no paintings or only paintings with a specific color value
(or a
null
color value)?
I am using Cayenne 2.0.4 in case that matters.
TIA
--
Andrey
